An important matter in road-traffic technology is the determination of tailback lengths at traffic-light installations in order to obtain information items relating to the traffic flow. The knowledge of the tailback lengths may, in addition, serve to control the signal installations (Bernhard Friedrich, Methoden und Potentiale adaptiver Verfahren für die Lichtsignalsteuerung (Methods and potentials of adaptive methods for traffic-signal control), Straβenverkehrstechnik 9/1996). According to Joos Bernhard, Thomas Riedel, Erkennung von Stau mit kurzen Schleifendetektoren (Detection of tailback using short loop detectors), Straβenverkehrstechnik 7/1999, tailbacks at traffic-light installations can be detected or calculated only between a stop line and detector. The same applies also to tailbacks at any operating stations for processing individually moving units having alternating hold-back and release phases.
A substantial disadvantage of this known method consists in not being able to determine tailback lengths that are greater than the distance between an operating station and detector.
The object of the invention is therefore to provide a method with which a determination of the tailback length at operating stations for processing individually moving units is made possible not only between an operating station and detector in order to control a traffic-light installation or filter with the aid of said tailback length or characteristic values derived therefrom, such as, for example, waiting times, or to display traffic statuses in primary devices.